External ear

The external ear comprises the auricle (or pinna), the external auditory meatus, and the tympanum (eardrum). The pinna concentrates and amplifies sound waves and funnels them through the outer acoustic pore into the external auditory meatus, which carries them to the tympanic membrane.

Gross anatomy

Auricle (pinna)

The auricle is the part of the ear that projects laterally from the head. It is composed of an irregular concave plate of elastic cartilage and dense connective tissue, covered by skin which contains short hairs (tragi), sebaceous glands, and ceruminous glands.

Structure

The auricle has a complex shape that is composed of several ridges, notches, and grooves (see Figure 1):

helix: posterior free margin of the auricle

anthelix: a ridge parallel to the helix

crura anthelicis: a pair of limbs located above the external acoustic pore

fossa triangularis:tiny depression between thecrura

scaphoid fossa: the depression between the helix and anthelix

tragus: prominence in front of the external acoustic pore

can be manually pushed back over the pore, to mitigate noise

antitragus: situated in the lower part of the anthelix and faces the tragus

intertragic incisure: a notch separating the tragus from the antitragus

cavum conchae: the deepest depression in the auricle, inferior to the crus of the helix

cymba conchae: depression surrounded by the crus of the helix below and the inferior crus of anthelix above

ear lobe: the lowest part of the ear and the only part that does not contain cartilage, situated below the intertragic incisure